package com.example.mqrabbit.myjava.oneToMany;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.QueueingConsumer;

public class Worker {

 /*   接收端和场景1不同点：
1、使用“task_queue”声明消息队列，并使消息队列durable
2、在使用channel.basicConsume接收消息时使autoAck为false，即不自动会发ack，由channel.basicAck()在消息处理完成后发送消息。
3、使用了channel.basicQos(1)保证在接收端一个消息没有处理完时不会接收另一个消息，即接收端发送了ack后才会接收下一个消息。在这种情况下发送端会尝试把消息发送给下一个not busy的接收端。
    */
    private static final String TASK_QUEUE_NAME = "task_queue";

    public static void main(String[] argv) throws Exception {

        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();

        channel.queueDeclare(TASK_QUEUE_NAME, true, false, false, null);
        System.out.println(" [*] Waiting for messages. To exit press CTRL+C");

        channel.basicQos(1);

        QueueingConsumer consumer = new QueueingConsumer(channel);
        channel.basicConsume(TASK_QUEUE_NAME, false, consumer);

        while (true) {
            QueueingConsumer.Delivery delivery = consumer.nextDelivery();
            String message = new String(delivery.getBody());

            System.out.println(" [x] Received '" + message + "'");
            doWork(message);
            System.out.println(" [x] Done");

            channel.basicAck(delivery.getEnvelope().getDeliveryTag(), false);
        }
    }

    private static void doWork(String task) throws InterruptedException {
        for (char ch: task.toCharArray()) {
            if (ch == '.') Thread.sleep(1000);
        }
    }
}